Thursday, May 28, 2015

HP Prime, TI-84 Plus, Casio Prizm: Julian Day Shortcut Formulas

Julian Day Shortcut Formulas

Here are a couple of formulas that can be used to quickly get the Julian Day.  (I haven't figured how to include the time yet).


HP Prime (Rev. 7820):

yyyy:  four digit year, mm:  two digit month, dd: two digit day.  The international date format is used.

From December 31, 1899:

JD = DDAYS(1899.1231,yyyy.mmdd) + 2415020

Alternatively, from November 16, 1858:

JD = DDAYS(1858.1116, yyyy.mmdd) + 2.4E6


TI-84 (and BA II  Plus to that extent):

Dates are good from January 1, 1950 to December 31, 2049:

JD = dbd(1.0150, mm.ddyy) + 2433283

The days between dates function (dbd) is accessed by pressing [ APPS ], [ 1 ], [ALPHA], [ x^-1] (D).  

Casio Prizm and fx-Graphing calculators:

Dates are good from January 1, 1901 to December 31, 2099:

JD = Days_Prd(1,1,1901,mm,dd,yyyy) + 2415386

Where to find Days_Prd:  [ OPTN ], ( > ) (until you see the FINANCE sub menu), (FINANCE), ( > ), (DAYS), (PRD)

Hope you find this helpful.

Source:
"Julian Day"  http://en.wikipedia.org/wiki/Julian_day   Retrieved May 28, 2015


Eddie


This blog is property of Edward Shore.  2015.


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